Remove assumption of ember-cli-typescript-blueprints from docs

(cherry picked from commit e3d1227)

Author: dfreeman

docs/configuration.md

@@ -1,23 +1,5 @@
 # Configuration
 
-## Blueprints
-
-By default, ember-cli-typescript installs the [ember-cli-typescript-blueprints](https://github.com/typed-ember/ember-cli-typescript-blueprints) package so that you can use Ember's generators like normal, but with all the special sauce you need for things to work nicely throughout your system with TypeScript.
-
-If you want to stick with the normal JavaScript blueprints—say, because your team isn't ready to dive into the deep end with making _everything_ TypeScript yet—you can simply uninstall the blueprints package.
-
-With yarn:
-
-```bash
-yarn remove ember-cli-typescript-blueprints
-```
-
-With npm:
-
-```bash
-npm uninstall ember-cli-typescript-blueprints
-```
-
 ## `tsconfig.json`
 
 We generate a good default [`tsconfig.json`](https://github.com/typed-ember/ember-cli-typescript/blob/master/blueprint-files/ember-cli-typescript/tsconfig.json), which will usually make everything _Just Work™_. In general, you may customize your TypeScript build process as usual using the `tsconfig.json` file.

docs/ts/with-addons.md

@@ -54,8 +54,6 @@ compilerOptions: {
 
 [In-repo addons](https://ember-cli.com/extending/#detailed-list-of-blueprints-and-their-use) work in much the same way as linked ones. Their `.ts` files are managed automatically by `ember-cli-typescript` in their `dependencies`, and you can ensure imports resolve correctly from the host by adding entries in `paths` in the base `tsconfig.json` file.
 
-Note that the `in-repo-addon` blueprint should automatically add these entries if you have `ember-cli-typescript-blueprints` installed when you run it.
-
 ```javascript
 compilerOptions: {
   // ...other options